First US 2013
H3N2 Sequence Has T128A
Recombinomics
Commentary 14:15
February 2, 2013

The CDC has released its first
set of 2013 H3N2 sequences (at GISAID), A/Virginia/03/2013, from a
patient (76F) in Virginia, collected on January 4. The H3
sequences had T128A,
which abolishes the glycosylation site at position 126. This
change is becoming increasingly
common in H3N2 sequences in the United States as well as across the
world, including recent sequences in Europe and Africa. This same
change was present in the vaccine target for the 2004-05 season,
A/Wyoming/03/2003, which was developed after the severed 2003-04 season
which featured an H3N2 related to A/Fujian/411/2002. This Fujian
H3N2 produced a Pneumonia and Influenza Death Rate of 10% in the United
States which was associated with 154 pediatric deaths. The high
fatality rate led to requirements for the reporting of all flu lab
confirmed pediatric deaths in the United States, and some states also
made the reporting of all adult fatal influenza cases under the age of
65 reportable also.
The Virginia sequence is closely related to A/Iowa/14/2012, which is
one of the two H3N2 sequences this season that the CDC has designated
as a low reactor, indicating the current H3N2 vaccine poorly recognizes
this sequences, which is almost certainly largely due to the loss of
the glycosylation site at position 126, which was also linked to the
spread of H3N2 in 2003-04. In addition to the 2013 Virginia
sequence, the CDC also released 6 additional December 2012 sequences,
and 4 of the 6 are closely related to the Virginia sequence and have
T128A (A/New Hampshire/21/2012, A/Wisconsin/51/2012, and
A/Kansas/16/2012).